Thermal Shock and Residual Strength Testing of SiC/SiC Composite Braided Tubes

BackgroundCeramic matrix composites are promising materials for high temperature application in aerospace and nuclear engineering. In these applications, thermal shock is an important potential cause for failure.ObjectiveIn order to study thermal shock resistance of SiC/SiC composite braided tubes, a novel method has been developed to apply thermal shock cycles to tube sections and then measure the residual tensile strength.MethodsSiC/SiC composite braided tubes have been thermally shocked by many cycles in a short time using a novel test platform based on quartz lamp irradiation heating. The circumferential tensile strength was measured using C-ring specimens after thermal shock testing of short tube sections. Numerical simulations of the stress from the thermal shock test were conducted using the finite element method.ResultsThe circumferential tensile strength decreased with increasing number of thermal shock cycles in air. An embrittled region with limited fiber pullout due to oxidation extended from the surface.ConclusionsThe test platform can simulate service environments with fast temperature cycling for small test specimens in air.

Automated summary

The study investigates the thermal shock resistance of SiC/SiC composite braided tubes and measures the residual tensile strength using a novel method. The results show that the circumferential tensile strength decreases with increasing thermal shock cycles, accompanied by oxidation-induced limited fiber pullout near the surface. The test platform can simulate fast temperature cycling service environments for small test specimens in air.